Article,
Low frequency noise and annoyance
Noise & Health, (2004)
Abstract
Low frequency noise, the frequency range from about 10Hz to 200Hz,
has been recognised as a special environmental noise problem, particularly
to sensitive people in their homes. Conventional methods of assessing
annoyance, typically based on A-weighted equivalent level, are inadequate
for low frequency noise and lead to incorrect decisions by regulatory
authorities. There have been a large number of laboratory measurements
of annoyance by low frequency noise, each with different spectra
and levels, making comparisons difficult, but the main conclusions
are that annoyance of low frequencies increases rapidly with level.
Additionally the A-weighted level underestimates the effects of low
frequency noises. There is a possibility of learned aversion to low
frequency noise, leading to annoyance and stress which may receive
unsympathetic treatment from regulatory authorities. In particular,
problems of the Hum often remain unresolved. An approximate estimate
is that about 2.5% of the population may have a low frequency threshold
which is at least 12dB more sensitive than the average threshold,
corresponding to nearly 1,000,000 persons in the 50-59 year old age
group in the EU-15 countries. This is the group which generates many
complaints. Low frequency noise specific criteria have been introduced
in some countries, but do not deal adequately with fluctuations.
Validation of the criteria has been for a limited range of noises
and subjects.
